Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

Zond 6 was the second spacecraft that the Soviets sent around the Moon.

Soon after translunar injection, ground controllers discovered that the vehicle's high-gain antenna had failed to deploy. Given that the main attitude- control sensor was installed on the antenna boom, controllers had to make plans to use a backup sensor for further attitude control.

The spacecraft circled the far side of the Moon at a range of 2,420 kilometers, once again taking black-and-white photographs of the Moon.

During the return flight, temperatures in a hydrogen peroxide tank for the attitude-control thrusters dropped far below acceptable levels. Engineers attempted to heat the tank by direct sunlight, but as they later discovered, such a procedure affected the weak pressurization seal of the main hatch and led to slow decompression of the main capsule.

A radio altimeter, not designed for work in depressurized spacecraft, issued an incorrect command to jettison the main parachutes. As a result, the spacecraft plummeted to the ground and was destroyed. Although the main biological payload was lost, rescuers salvaged film from the cameras.

Key Dates

10 Nov 1968: Launch

Status: Partial Success

Fast Facts

This was the second soviet spacecraft to fly around the Moon and return to Earth.

The spacecraft crashed on Earth.

Although the biological payload was descroyed, rescuers salvaged film from the spacecraft cameras.